I always keep a bottle of milk-of-magnesia (magnesium hydroxide solution) in the house. Pharmacists usually sell it very cheaply, a bottle lasts ages, and it works for me just as well as more expensive tablets etc. You have to be careful not to overdo it, though, as it's also a rather effective laxative if you take too much! It's not so handy for carrying around either, so I use whatever indigestion tablets are easily available if my acid gets up while I'm out of the house.
If I wasn't so fond of curry and chilli, I probably wouldn't need it so often!
_________________
When you are fighting an invisible monster, first throw a bucket of paint over it.